Commutator



Feb. 16, 1932. v. G. APPLE commu'm'ron Filed July 26, 1929 I to produce a commutator in which these ob- Patented Feb.16, 1932 1 I UNITED sTA TE'S' rAraNT OFFICE vmcm rr e. arm or Barron, onro' coimo'ra'ron 1 1110111011 111m m as, 1029. Serial in. 881,360.

To provide commutators of this class suit-- able for high rotative speed the core materialv must possess considerable mechanical as well as dielectric strength, and a certain classof phenol-resin molding compounds meet this requirement and are therefore often used 1 the segment shown in Fig. 6 is mad for this purpose.

-' But when cores made from theselstrong materials extend outwardly betweenthe metal segments and form a part of the brush track "of the commutator, d'ifliculty is encountered,

since these materials do not make a good brush track because arcing of the brushes converts them to carbon which is a conductor, and thereby adjacent segments are electrically joined.

To overcome this objection commutators ofthis class are usually undercut, -i. e. the core 1 material is cut from between, the segments at the brush track, or sometimes spacers of sheet insulating material more nearly suited to a brush track are placed between the segments near the periphery of the commutator, and the core isthen molded to extend outwardly be-.

' tween the segments until met and excluded by these spacers.

It is the fore an object ofthisinvention jections' are not present, by providing apparatus and a procedure which.

' and another. kind for the spacers which separate the segments at their outer edges ad] acent the brush track,- each kind being determined essary adhesive properties to keep-them se-- cured against radially outward ,movement during rotation of thecommutator, it is a of segments of material shown the spacing means of t contemplates employin'g one kind of insulation for thec'ore I further object of the invention to provide specific means to hold them in place.

Other objects and meritorious features of v the invention will become apparent, to one skilled in the art of commutator making, from a consideration of the following description taken in conj unction with the drawings,wherein. 4

Fi s. 1 to 6 are perspective views of difierent orms of segments, either of which is suitable formaking a commutator embody ing my invention.

ig. 7 is an outline of the blank from which Fig. 8 is a plan view' ofthe mold with the stock ring and the plunger removed to more clearly show the means for holding a plurality of segments, of either of the kinds in Figs. 1 to v5, in spaced apart relation while a core of insulation is molded in place. 7 I

Fig. 9 is a fragmentar plan view of another mold similar to t at shown in Fig.

15 but modified to hold a set of segments Fig. 6. v

Fig. 10 is a fragmentary view of the mold Fig. 8 with segments Fi 4 in lace between mol and a core of insulation molded to hold the segments in spaced relation after the structure is removed from the mold.

Fig. 11 shows the. commutator structure asit appears after removal from the mold in which it appears in Fig. 10.

Fig. 12 shows a commutator structure similar to that shown in Fig. 11- except that it is composed of segments Fig. 3 instead of seggnents Fig. 4.

. ig. 13 is a transverse section through a second. mold similar to that shown-in Fig.

8 except that the-segment spacing meansare omitted;

Fig. 14 is a vertical Similar" numerals refer' to similar parts are preferably made section shown andcutting. it into lengths.

The segments 25 and 26, having no grooves Y axial section through the second mold taken at 14 -14 of Fig. 13.

of the cross 5 dial movement by enlargements at the inner ends of said partitions, molding a core of insulation about certain portions of said segments to bind them together in the spaced apart relation which they occupy in the mold 1 due to said partitions, removing the partitions so as to form slots having enlar ed bottoms, then molding insulation of a ifferent nature than that in said core into the said slots.

l5 3. The method of making a commutator, whichconsists of arranging the segments in spaced apart cylindrical formation, supporting them a ainst circumferential movement in a mold by partitions extending radially inward from the wall of said mold, and supporting them against radially inward movement in said mold by T-shaped inner ends on said partitions, molding a core of insulation about said segments, hardening said core, removing said spacers so as to form T- sha ed slots, then molding insulation into sai slots.

In testimony whereof I aifix my signature.

VINOEN T G. APPLE. 

